Diffuse radiation from DarkCOs with a vector-portal dark photon

Ascertain whether dark compact objects would produce detectable diffuse radiation if the dark photon couples to the Standard Model via a vector portal by computing the expected emission spectra, luminosities, and sky backgrounds and comparing them with astrophysical limits.

Background

The paper assumes no coupling between the dark photon and the SM. If a vector-portal coupling exists, ongoing cooling of DarkCOs via dark bremsstrahlung could yield SM-visible diffuse radiation.

Establishing the observability of such signals would provide a novel avenue to test or constrain the scenario.

References

While in this work we have assumed the dark photon $\gamma_D$ has no coupling to SM particles, it will be interesting to consider whether there is detectable, diffuse radiation from these objects if $\gamma_D$ couples to the SM through, $e.g.$ a vector portal operator. We leave further investigation of these and other rich phenomena associated with DarkCOs and late-forming PBHs to future work.

— Dissipative Dark Cosmology: From Early Matter Dominance to Delayed Compact Objects (2405.04575 - Bramante et al., 7 May 2024) in Section 6 (Conclusions)